Potentially misleading error about duplicate cells

[kwstat]

The first desplot complains about multiple data for each x/y/panel.
The second desplot does not.
I suspect the check for multiple cells is not able to handle two terms in year*site.

  library(agridat)
  data(tesfaye.millet)
  dat <- tesfaye.millet

  libs(desplot)
  dat <- transform(dat, year=factor(year), site=factor(site))
  desplot(dat, yield ~ col*row|year*site, out1=rep, main="tesfaye.millet")
# Warning message:
# In desplot(dat, yield ~ col * row | year * site, out1 = rep, main = "tesfaye.millet") :
# There are multiple data for each x/y/panel combination

  libs(dplyr,asreml,lucid)
  dat <- mutate(dat,
                env=factor(paste0(site,year)),
                gen=factor(gen),
                rep=factor(rep),
                xfac=factor(col), yfac=factor(row))
  desplot(dat, yield~col*row|env)